Patent GB-191208811-A (GB)
Title: Improvements in and relating to Railway Signalling.
Inventor: TARRANT REUBEN WILLIAM
IPC: B61L23/12
Filed: 1912-04-13
Granted: 1913-04-10
Abstract: 8811. Tarrant, R. W. April 13. [Cognate Application, 23,468/12.] Combined electrical and mechanical systems, non-automatic; single-track systems; track apparatus actuating signals other than on trains; signalling-instruments; miniature signals; slots, reversers, and like apparatus; handlevers and hand gearing, interlocking; locking of unspecfiied application. - Traffic in either direction over a section of single-line railway is controlled from the advance end of the section for the time being by similar block instruments at each end of the section, which co-operate with manually operated ' home' and ' starting ' signals provided with electromagnetic signal reversers controlled by train operated switches; one line wire may be used for the entire service of each block section including the bell and telephone, although these may be operated over a separate line wire, if desired. The state of the signals and traffic are constantly indicated in each block instrument by mechanical and electro-mechanical apparatus. Arrangements are made for cancelling any permission for a transit. Fig. 1 shows the general arrangement of the block instrument, hand-levers, signals, and train treadles at one station, say A, which is connected by the line wire ab to a second station, say B, which is not shown. The block instrument is shown in side elevation in Fig. 2. Figs. 9 and 10 show details of electro-mechanical switches actuated by the commutator spindle. Fig. 12 shows a locking device on the commutator spindle. Fig. 19 shows the cancelling switches. The parts are shown in their normal position on all these Figures. Each instrument comprises a rotary commutator drum 21 on a hollow spindle 24 carrying a series of cams 78, 27, 35, 102, which coact with lifting-rods to lock the spindle and to actuate the indicating-tablets 34, 39, 43. A spring-pressed plunger 23 with a knob 25 and cams 109, 110 slides within the spindle 24. When both instruments are normal, the commutators 21 occupy a mid-position from which they are free to be moved in a counter-clockwise direction towards the acceptance position, but are locked against reverse rotation to the sending position. The words ' line blocked ' on the tablet 39 are exposed, and the tablet 34 shows a blank, In order to pass a train from A to B, permission is asked and obtained by bell signals over the bell circuit, which includes the battery 50 and switch 179 at A, the line wire ab, switch 179 at B, polarized relay 49, and the earth return. The polarized relay 49 closes at the lower contacts the circuits of the bell 51 from the battery 223 at B. The operator at B replies by means of a corresponding circuit. The commutator 21 at B is then rotated to the left to the accepting position, in which it becomes locked by the bolt 26 entering a notch in the disk 27 of the locking-device shown in Fig. 12, which is a modification of that described in Specifications 1422/09 and 12,757/11. In its present form the core 29 is held in its raised position by a stop 75 carried by a leaf spring 76 fixed at its lower end to the frame of the apparatus. When the commutator is subsequently turned, the spring bolt 68 is lifted by a cam 78, and rocks the bell-crank 81, which coacts with a fixed pin 84 to flex the spring 76 and remove the stop 75 from the core 29, which then falls to re-engage the rotary sectors of the locking-device. The cams 35, 102, 110 on the spindle 24 lower the rod 88 which moves the tablet 34 to expose the word ' from,' and also lower the rod 101 from the tablet 43, which is, however, retained by the polarized electro-magnet 45, and raise the rod 96 to hold the tablet 39 in its original position. The instrument at B thus shows ' line blocked from A.' The plunger 25 at B is released by the rotation of the commutator since the cam 110 lifts the rod 96 until the spring bolt 117 rests upon the circular disk 109. The plunger 25 is then pressed in and the rod 96 falls so as to rest upon the cam 110 until the plunger is released. The rod 96 being lowered, the tablet 39 shows its top section marked 'line clear; train ' accepted. ' While the commutator is moved to the ' accept ' position, a circuit is completed from earth at B, through battery 227, contacts 129 of magnet 122 (which are closed by the stud 124 engaging the hinged pawl 125), the magnets 122 and 167 in parallel, the wire 238, and the cancelling switches 182,183 to earth. The magnet 122 keeps the contacts 129 closed. The indicator 167 shows that the home signal is free; and when the pedal switch 158 at B is closed current passes from the battery 227, through contacts 129 as above, and thence by wire 244 and switch 158 through the magnet 157 of the homesignal-lever lock, which is of the type described in the before-mentioned Specifications. The lever 151 is then operated to clear the home signal at B and the contacts 160 open the circuit through the magnets 122, 167, 157. When the plunger is pressed, a current is passed from earth, through the plunger battery 230, the plunger switch 120, and the cancelling- switches, to the line wire ab, and thence through the cancelling-switches at A, plunger switch 120 which is in the normal position shown in Fig. 1, and terminal 175 to the polarized relay 49 and polarized magnet coil 45 in parallel, and thence to earth. The magnet 44 is de-energized, but the rod 101 holds the tablet 43. The polarized relay 49 closes the contacts 170, and current passes from the wire 236 through these contacts 170, contacts 161 on the home signal lever and 148 on the starting signal lever at A, commutator contacts 60, and electro - magnet 31 to earth. The pin 95, lifted by the core of the magnet 31, rocks the lever 94 and raises the pin 95 and the tablet 39 to show the words ' line clear.' The commutator at A is also released by the magnet 31, and the operator turns it to the right, that is to ' sending ' position, in which it is locked by the bolt 26 dropping into another notch in the disk 27. The rod 88 supports the tablet 39 and raises the tablet 34 to show the word ' to ' ; the rod 101 no longer supports the tablet 43, which is, however, held by the magnet 45; the pairs of spring contacts 63, 64 are bridged; contacts 137 are closed by the stud 132 engaging the pawl 133 and close the circuit of the holding-magnet 130. The pedal switch 145 at A being next closed, the hand-lever 138 for the starting signal is released, this signal pulled off, and the circuit of the magnets 130, 166, 144 broken down at the switch 147. The section is thus in order for a train to pass from A to B, and the instruments are locked against further operation by the operators, except for ' cancellation ' as described below. The train entering the section passes the treadle 52 and closes a circuit from earth, through battery 202, to the signalreversing magnet 53<a>, whereby the starting signal 53 is set to ' danger.' Current also passes from the battery 202 over contacts 150, contacts 63 to the wire 260 where it divides over two circuits, the first to the magnets 45, 49 in parallel at the sending station A to earth, the second passing over the line wire ab to the receiving station B and through the magnets 45, 49 in parallel to earth. The current passing through the windings 45 of the polarized electromagnets 44 is of such polarity as to cause the armatures 99 to be released, and the tablets 43 fall until stopped by the pin 104 resting on the bell-crank 103 and expose the words ' train in ' section.' The train passes through the section and on leaving closes the treadle switch 54, thereby energizing the signal-reversing magnet 55<a> and setting the home signal to danger; current also passes over contacts 162, contacts 61, and electro-magnet 31 to earth. The magnet 31 releases the lock on the commutator at B and withdraws the bell-crank 103 from the pin 104 so that the tablet 43 falls to show the words ' section cleared.' The commutator at B is replaced to normal and resets mechanically all the tablets 34, 39, 43 to normal. The plunger 23 is also released and is pressed a second time, sending a current from battery 230 by way of switch 120, line wire ab to magnet 45 and relay 49 at A in parallel, the latter closing a circuit through the magnet 31. The magnet 31 at A causes the tablet 43 to show the words ' section ' cleared ' and unlocks the commutator, which can be reset, thus restoring the instrument to normal condition. If it is required to cancel the permission for a train to pass over a section after the signals have been set clear, but before the train has entered the section, the home and starter signal levers at the sending station and the home signal lever at the accepting station must be set to normal position. Hence backlocks are not fitted on the levers. The switches 184, 185, 190, 191 are provided, operated by two plungers 182, 183 interlocked by stops 197, 198 with a disk 200 on the spindle 24, so that one only of these plungers is free in either the accepting or sending positions, but both are locked if the commutator is normal. To cancel an authorization after setting the signals, the operators communicate with one another and set all their signal levers to danger. If, however, the signals have not been pulled off, the magnets 122, 130 will remain energized and the switch 184, actuated by the accepting cancellation button 182, and the switch 190 actuated by the sending cancellation button, are provided for this purpose. Both operators press in their cancellation buttons which are free and hold them for a prearranged time interval. A current passes from earth at A, through contacts 160,147, through the high-potential cancellation battery 234, switch 171 (which is inserted for the purpose of preventing cancellation after a train has entered the section), and switches 191, 185 at A to the line wire ab through the following circuits at B, viz. switches 185, 190, polarized relay